Javawug bof 57 scala why now
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Scala is a functional and object-oriented programming language that runs on the Java Virtual Machine (JVM). Martin Odersky created Scala in 2003 with the goal of making a better Java. Scala combines object-oriented and functional programming which allows for features like closures, immutable data structures, pattern matching and more. It is intended to be more concise and powerful than Java.
![Repeat Until Construction #1b
import demo.Control;
object LoopDemo {
def main( args: Array[String] ) {
var y=0;
repeatLoop {
println("found y="+y)
y += 1
}
{ until ( y < 10 ) }
}
}](https://image.slidesharecdn.com/javawugbof57scalawhynow-100714083939-phpapp01/85/Javawug-bof-57-scala-why-now-9-320.jpg)
Javawug bof 57 scala why now
- 2. Brief History Scala Scala – Scalable Language Pre‐history 1996 – 1997 Pizza, 1998‐2000 GJ 2003 Experiment 2006‐2009 Industrial strength programming language “Make a better Java”
- 4. Why Scala? • Closures • Lambda Currying Functional • Immutables • Style • Full Types Object • Hierarchical, Mix‐ Oriented Ins • Case Classes • Operators Overloading Scalable • Pattern Matching • Extendable with Libraries • Static compilation Cross to byte codes Platform • JVM • Dot Net
- 5. Functional Side Closures , Lambda Expression, Function Types Immutable References to Objects (val) Immutable Objects & Collections Standard Scala Libraries Currying – Control Abstractions Last Statement is an Expression Tail Recursion
- 6. Object Oriented Side Everything is an Object in Scala Better Static Classes (Object) Classes with reduced boilerplate Traits , Mix‐ins, Self‐Types
- 7. REPL ‐ Read, Evaluate, Print, Loop Execute Scala like a Scripting language Increasing support Eclipse IDE , NetBeans, IntelliJ New Tools, Ideas and Innovations SBT, Actors, Lift
- 8. Repeat Until Construction #1a package demo; object Control { def repeatLoop ( body: => Unit ) = new Until( body ) def class Until( body: => Unit ) { def until( cond: => Boolean ) { body; if ( cond ) repeatLoop(body).until(cond) } } }
- 9. Repeat Until Construction #1b import demo.Control; object LoopDemo { def main( args: Array[String] ) { var y=0; repeatLoop { println("found y="+y) y += 1 } { until ( y < 10 ) } } }
- 10. Quick Introduction to Currying Haskell Curry (1901 – 1982) American Mathematician & Logician Combinatory Logic Partial Functions U(x,y,z) == F(x) ‐> G(y) ‐> H(z)
- 11. Repeat Until Construction #2 object Control { def repeat(body: => Unit) = new { def until(condition: => Boolean) = { do { body } while (!condition) } } } // Jesper and Rex Kerr
- 12. Concurrency in Scala Actor based concurrency library (Bill Venners) Asynchronous messages Dispatch to threads; Fork Join
- 13. Taste of Concurrency #1 import scala.actors._ import scala.actors.Actor._ object TradeMessageProcessor extends Actor { def act() { loop { receive { case f: FXOrder => f.spotPrice() case m: MMOrder => m.maturityPrice() case “stop” => println(“Stopping now...”; exit case x: Any -> println(“Error: unknown msg: “+x) } } } }
- 14. Taste of Concurrency #2 TradeMessageProcessor.start() TradeMessageProcessor ! new FXForwardOrder ( /*...*/ ) TradeMessageProcessor ! new FXSpotOrder( /*...*/ ) TradeMessageProcessor ! new MMOrder( /*...*/ ) TradeMessageProcessor ! 2.87134 // Unknown Msg Error! TradeMessageProcessor ! “stop” // Processor stops
- 15. Thanks For Your Attention! For more information http://scala‐lang.org http://daily‐scala.blogspot.com/ http://stack‐overflow.com search on Scala Scala is the Java of the Future http://jroller.com/javawug